would be better just to sell the truck and get a 2500. everything is different for one. and two if you have even slight hills a tbi 350 is not going to be happy for long towing that much weight. let alone the incredibly weak if pushed 4l60. that would be why you would have to change everything, the gears would have to go, completely everything.

go find a 2500 or 3500 with a 454 you will be alot cheaper and happier

I thought of that but the budget doesn't allow it. I do know all the running gear is different. I am planning to use a 4.10 ratio gears in the changeover which will help. And the 350 tbi is a high output engine not the origional anemic 350. I am hoping with the lower ratio the trans can live. As I plan on adding a trans cooler it should I think. I can get a donor truch for 800.00 and do most if not all the work ourselves..

What I see needing done should (I Think) mostly bolt on the exsisting frame.

whats the weight of the trailer? i doubt the engine is much more power than the original, you would have to change the pcm and a bunch of other things. the gears and trans cooler wont be enough to make a regular 4l60 last to any of the larger 5th wheels. now that the gas is so high you maybe able to trade someone for a better truck with a 454 and all that stuff already. when i bought my yukon a couple years ago the average price of a 1500 sub/tahoe/ or 1500 pickup was 3-4k if they were decent and the 2500'* were 2-3k with the same miles if they had a 454

Justin is giving you rock solid information. You will spend more in parts alone( trying to convert your 1/2 ton than buying a used 3/4 or one ton truck, and when done it still won't have the overall capability to safely transport the trailer.

your official weight rating if you get into a wreck or you get stopped is around 6k. nothing you can change except the truck will make it 8500. if the trailer was one of the new light ones maybe but thats way too much